The invention relates to an artificial heart having at least two inlet openings and two outlet openings for blood and comprising four operating chambers of variable volume.
The field of use of the artificial heart is medicine, namely the implantation of the said heart in a human body instead of an incurable biological heart.
It is known that in industrial countries heart disease is the main reason of death. A heart transplantation is up to now the last and only radical cure. In such a case a healthy heart from a donor is used, which comes e.g. through a fatal accident. In early days there were few transplantations and the donor problem was of secondary importance. The main problems were the operation technique and suppressing the patient's natural immunity after the operation to prevent the reject reaction. Now thousands of operations are executed every year, and the donor problem is the main one. Also the reject-reaction problem can not be seen as well solved; the patient constantly depends on medicaments and is under risk of its side-effects.
The solution of donor and also largely of reject-reaction problem is the development of a mechanical artificial heart. Instead of conventional heart machines which operate in operation rooms today an implantable artificial heart must have:
1) small volume and low weight; PA1 2) long working life (e.g. ten years); PA1 3) low vibration; PA1 4) a driver which is placed outside the human body and works without damaging the skin; PA1 5) low energy consumption. PA1 two stationary plates which are arranged parallel and spaced to each other, and which together with a cylinder wall build a case, which has inlet and outlet openings for blood and is implanted in the human body instead of an incurable biological heart, PA1 twelve elongated wall elements which are disposed between said plates and which bear slidingly and sealingly on said plates, and together with said plates form four operating chambers, PA1 each wall element being articulately sealingly connected at its end points (articulation points) to at least one further wall element in such a manner that said wall elements from a movable grid having nine axles, the central axles of the said grid being connected at least with one of the said plates and at least two of the remaining axles of the said grid are equipped with permanent magnets and, PA1 the driver being placed outside the human body, which is formed as a round plate, as a bar, or as a grid being similar to the grid contained in the case, and which is equipped at least with two magnets.
Presently available piston-, rotor-, membrane or flexible-pipe pumps can not satisfy these requirements.
The pump FIG. 1a,b which was built in accordance with U.S. Pat. No. 5,004,409 seems to be a way to fulfill the items 1)-5). It has four operating chambers 18a-d which are placed in a case 20 consisting of two end plates 2, 10 connected with a cylinder wall. The operating chambers 18a-d are formed by two parallel plates 2, 3 and a grid 4 consisting of twelve elongated wall elements which are disposed between said plates 2, 3 and which bear slidingly and sealingly on said plates, each wall element being articulately sealingly Connected at its end points (articulation points) to at least one further wall element in such a manner that said wall elements form a movable grid 4 . The grid 4 has nine joints and nine axles, respectively. The central grid's axle 7 is connected with the plate 2, the two opposite outside axles 6a,b are connected with the plate 3. The remaining six grid's axles are free. The plate 3 can be rotated around the shaft 5. During this rotation the forms and volumes of operating chambers 18a-d are changed.
In the plate 2 there are four openings 13a,b, 14a,b for blood. In FIG. 1a the plate 2 is omitted to show the grid. In spite of it the locations of openings are shown in FIG. 1a with thin lines. Connections of openings with the operating chambers are controlled by the grid's elements. In the configuration of the grid 4 shown in FIG. 1a all openings are closed, the chambers 18a,c have their maximum volume, whilst the chambers 18b,d have their minimum volume. If the plate 3 is rotated in the direction shown in FIG. 1a with the arrow, the openings 13a,b, 14a,b would be connected with the chambers 18c, 18a, 18d and 18b, respectively. The volume of the chambers 18a,c would be diminished and the volume of the chambers 18b,d would be increased. Therefore the openings 13a,b serve as outlets and the openings 14a,b serve as inlets for blood.
The case 20 would be implanted into the human body instead of an incurable biological heart in such a way that the plate 10 is placed near the skin. The ribs can be used to secure the position of the case. One outlet-inlet pair e.g. 13a, 14a can be connected to the small (lungs) blood circulation whilst another outlet-inlet pair 13b, 14b can be connected to the large (body) blood circulation.
The rotation of the plate 3 is initiated by the driver, namely by the plate 12 (FIG.1b) which is placed outside die human body near to the skin surface and is connected with the driving shaft 8. Both plates 3, 12 are equipped on their perimeters with the permanent magnets 11, 11' to create a magnet coupling.
The sealing is never perfect, and blood from the operating chambers leaks into part. 21 of the case's room outside the grid 4. Therefore this part must be washed properly with blood. The openings 15 and 16 serve for it. Through these openings part 21 can be connected (serial or parallel) to one of the blood circulations.
The disadvantages of the artificial heart FIG. 1a,b are yet a complexity and the large size and weight of its implant i.e. the case 20 and its contents.